Walking into the Aviator Nation store on Abbot Kinney in Venice is like stumbling into a frat house with a feminine touch. Steely Dan, Doors and Grateful Dead album covers and vintage skate decks nailed to the walls, a record player spinning Aerosmith's "Sweet Emotion," a "720 Degrees" arcade game in the corner, stacks and stacks of foam trucker hats, T-shirts and hoodies spreading good vibes like "Pray for Surf" and "California Is For Lovers".... It's such a sensory experience, you half expect your shoes to be sticking to the floor from last night's kegger.

Aviator Nation is the vision of Paige Mycoskie, who is turning a passion for 1970s nostalgia into the next California lifestyle brand.

"This is my little oasis of awesomeness," says the designer, 33, the picture of surfer girl blondness dressed on a recent afternoon in her signature uniform of checkerboard Vans, cut-off jean shorts, aviator sunglasses and an Aviator Nation tank top. "I hope people leave in a better mood than when they came in."

In just seven years, she's gone from sewing up T-shirts in her bedroom to designing a full brand of men's, women's and children's clothing and accessories that generated $5 million in sales last year, plus two freestanding Aviator Nation boutiques and a mobile Aviator Nation store housed in an Airstream trailer that will be cruising Orange County all summer.

While most T-shirt companies use computer-generated graphics and artwork, Mycoskie hand draws the lightning bolts, rainbow stripes, big wave surfers and psychedelic maidens that decorate many of her designs, then scans them into the computer. The slight imperfections lend an authenticity to the line, which also includes snowbunny-style pom-pom hats, reversible cord puffer vests, fleece sweatpants, and dolphin shorts made from dead-stock Hawaiian shirt fabric, all in vivid bright colors and all of which bring to mind OP, CB Sports and other lovable surf and snow labels of yore. The gift-with-purchase Aviator Nation drink koozie is the perfect loungin'-by-the-water, good-ole-girl touch.

"Everything I design or put in the line is something I personally want," she says of the collection, much of which looks like it could have been swiped from a cool older brother's closet. "I don't look at trend reports or runway shows. I'm not in that world."

"She's an original, a true bohemian who understands men's [clothing] as well as women's, knows how to have something for each and how to blur the lines a little," says Jim Moore, creative director of GQ magazine, which named Mycoskie one of its best new menswear designers in America for 2013, an honor that includes the opportunity to collaborate with Gap on a capsule collection that will be sold in Gap locations worldwide. "I always urge young designers to pull every penny together and open a store as soon as they can," he says. "That's what she did, and it became her laboratory."

A native of Arlington, Texas, Paige Mycoskie grew up the middle child between two brothers. Her older brother Blake Mycoskie founded Toms Shoes on the model that for every pair of shoes sold, a pair is donated to someone in need, and her younger brother Tyler Mycoskie works in sales at Toms.

She was always into sports, waterskiing and playing on the volleyball team, but also happened to have an artistic streak and a penchant for rainbows — rainbow window blinds and switch plates in her bedroom, rainbow birthday cakes, Rainbow Brite dolls, rainbows on every drawing that ended up on the family's refrigerator. "All of the artwork I did as a child was basically the same stuff I'm doing now, but not as perfect," she says.

Going into business for herself wasn't out of left field. She showed entrepreneurial skill at a young age, figuring out that the best place to set up her lemonade and cookies stand for the summer was on the edge of the golf course where her grandparents and their friends played every day. She took home as much as $500 a day — as a 6-year-old.

She first came to L.A. for a summer internship at Shape magazine and returned in 2002 when she was cast, along with her brother Blake, in the second season of the CBS reality show "The Amazing Race." They came in third place on the show, ultimately missing the $1-million prize. Afterward, she moved to L.A. permanently, settling in Venice, and working as a freelance writer and a saleswoman at the Santa Monica surf shop ZJ Boarding House. She got the idea to make T-shirts after noticing the vintage ones that were a mainstay of her tomboy chic wardrobe were becoming more expensive and harder to find.

"My idea of dressing up still to this day is wearing a rare rock tee with jeans and cool shoes and a leather jacket," says Mycoskie, who has been collecting vintage T-shirts since age 14. She only buys originals, numbers her collection in the hundreds and includes among her favorites a Jimi Hendrix "Just Ask the Axis" tee from 1970 and Live Aid festival shirt from 1985.